Teriparatide reduces the fracture risk associated with increasing number and severity of osteoporotic fractures

The relationship between prior fractures and risk of new fractures was evaluated in 931 postmenopausal women with prevalent vertebral fractures randomized to daily placebo or teriparatide (20 μg) in the Fracture Prevention Trial. The median observation time was 21 months. Among placebo patients with one, two, or three or more prevalent vertebral fractures, 7%, 16%, and 23%, respectively, developed vertebral fractures (by Cochran-Armitage trend test, P <0.001), and 3%, 9%, and 17% developed moderate or severe vertebral fractures (P <0.001). Among placebo patients with mild, moderate, or severe prevalent vertebral fractures, 10%, 13%, and 28%, respectively, developed vertebral fractures (P <0.001), and 4%, 8%, and 23% developed moderate or severe vertebral fractures (P <0.001). Among placebo patients with zero, one, or two or more prior nonvertebral fragility fractures, 4%, 8%, and 18%, respectively, developed nonvertebral fragility fractures (P <0.001). In the teriparatide-treated group, there was no significant increase in vertebral or nonvertebral fracture risk in these subgroups. In summary, the number and severity of prevalent vertebral fractures independently predicted the risk for new vertebral fractures, and the number of prior nonvertebral fractures predicted the risk for new nonvertebral fractures in placebo patients. However, in teriparatide-treated patients, the increased fracture risk associated with prior number and severity of fracture was not observed.